Impact of Age on Prognosis in Papillary Thyroid Carcinoma: How Should Age be Incorporated into the Treatment Strategy?

Abstract

Age has been recognized as one of the strong prognostic indicators for thyroid cancer. However, treatment strategies for papillary thyroid cancer (PTC) are usually determined only by the extent of disease progression, without considering the patient's age. The aim of this study was to investigate how the surgical strategy for PTC should take into account patient age. To exclude the effect of treatment strategy, 837 patients treated with uniform treatment strategies (hemithyroidectomy without radioiodine therapy) between 1986 and 1995 were the subjects of this study. Using a Cox proportional hazard model, clinical risk factors related to disease-specific survival (DSS), disease-free survival (DFS), and distant metastasis-free survival (DMFS) were analyzed. A receiver-operating characteristic (ROC) curve analysis was performed to identify the optimal cutoff points. Significant risk factors related to DSS and DMFS were age, extrathyroidal extension (ETE), and numbers of metastatic lymph nodes (NMLNs), but age was not significantly related to DFS. The 20-year DSS and DMFS rates were fair in patients without ETE regardless of age or NMLNs. However, in patients with ETE, DSS and DMFS rates were significantly worse in elderly patients than in young patients. ROC curve analysis showed that the optimal cutoff age was 48years for discriminating DSS in patients with ETE. Regardless of age, PTC patients without ETE are candidates for a treatment strategy not using RAI, and more aggressive treatment may be recommended for elderly PTC patients with ETE.